Matthew Kaufmann, PhD

Using Lower Quality Kidneys to Reduce Costs, Increase Transplants for Older Adults, With Matthew Kaufmann, PhD

Using typically discarded, higher-risk, yet acceptable-quality kidneys to increase transplant rates by 25% in adults ≥ 65 years of age may be cost-effective or even cost-saving, according to a new economic evaluation of the deceased donor transplant process.

In addition to the economic benefits, offering older adults the chance to utilize a kidney with a high kidney donor profile index (KDPI) >85% may be associated with reduced adverse waiting list events, including death, along with increased survival, and improved health-related quality-of-life (HRQOL).

How Can Higher KDPI Kidneys be Beneficial for Older Adults?

“There's this paradox where there's this really long wait list for kidney transplants, but approximately 1 in 4 recovered donor kidneys end up going unused,” study investigator Matt Kaufmann, PhD, Midwest Analytics and Disease Modeling Center Postdoctoral Fellow, explained in an interview for 

Then subsequently, there was a study that found that 62% of the kidneys that go unused in the US would have been allocated under France's allocation system.”

Within the US allocation system, approximately 20% of deceased donor kidneys are discarded each year. Specifically, >50% of those with a KDPI > 85 are discarded. In most clinical cases, when compared with staying on dialysis, even a KDPI = 99 kidney is suggested to offer improved longevity to transplant candidates.

To address this gap, investigators selected a synthetic cohort of adult candidates ≥ 65 years of age with end-stage kidney disease (ESKD) on the transplant waiting list, a patient population with markedly reduced rates of transplants compared to those <65 years of age.

“One study found that older candidates had expressed a willingness to trade off kidney quality for shorter waiting times,” said Kaufmann. “We have this pool of potentially usable kidneys that will otherwise go unused, and a patient population that receives a disproportionately low share of kidney transplants that may be willing to accept lower quality kidneys. We thought it was logical to estimate the benefits of allowing older candidates access to lower but acceptable quality kidneys.”

Assessing the Cost-Effectiveness and Utility of Lower Quality Kidneys

To assess the cost-effectiveness of increasing the kidney transplantation rate among older patients with ESKD by using acceptable-quality deceased donor kidneys, Kaufmann and colleagues conducted an economic evaluation using a discrete-time microsimulation model.

They included patient and caregiver time (opportunity) costs for a modified health care sector perspective analysis. Investigators calculated caregiver time costs as the mean number of hours per month spent caregiving multiplied by mean wage estimates from the Bureau of Labor Statistics, and assumed all candidates had a caregiver. They likewise calculated patient time costs for the time spent receiving care.

They derived age and sex specific HRQOL weights after transplant, as well as age, sex, and time-since-transplant specific after transplant. To evaluate hypothetical policies, they simulated an increased transplantation rate with a shift in the distribution of kidney quality due to the use of lower-quality but still acceptable-quality donor kidneys.

Considering the status quo of 0% increase in transplantation rates, investigators examined policies that would increase the transplantation rate by 5%, 10%, 15%, 20%, or 25%. An assumption was made that upon implementation of these policies, the average quality of deceased donor kidneys would decline to closely resemble the distribution of kidney quality as measured by the KDPI used in France’s system. Thus, the KDPI distribution under the policies reflects an increased use of high-KDPI donor kidneys. Investigators conducted scenario analyses around the proportion of donor kidneys where they increased the KDPI in 5% increments for up to 20% of donor kidneys.

As for statistical analysis, the primary outcomes include discounted lifetime costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios (ICERs). They evaluated the cost-effectiveness of interventions using a $100 ,000 per QALY gained willingness-to-pay (WTP) threshold.

Clinically, investigators found an association between deceased donor transplantation rate with a substantially decreased deaths on the waiting list and decreased waiting list removals as well as increased total net number of people undergoing transplants. Additionally, using lower-quality donor kidneys was associated with an increased risk of delayed graft function (DGF), but reduced wait times were associated with a decrease in this risk.

At a 5% increase in transplant rate, the DGF rate increased from the status quo. However, as the rate increased to 25%, the DGF rate moved back toward the status quo because of offsetting risk factors, a recurring pattern for the graft failure rate. Although lower kidney quality was associated with an increased risk of graft failure, reduced pretransplant dialysis time had a protective association.

The scenario analysis revealed that even if as many as 20% of transplanted kidneys were of lower quality than their given KDPI, increasing the transplantation rate by 25% would still be associated with 141 (range, 118-161) averted waiting list deaths and 375 (range, 350-396) waiting list removals per 10,000 candidates and 175 (range, 25-385) additional DGF cases and 103 (range, 9-266) additional graft loss events per 10,000 recipients.

Economically, when transplantation rates were increased by 25%, investigators noted an improvement in HRQOL cost-effectively, along with the most QALYs and lowest costs.

From the health care sector perspective, this would cost $8100 (95% credible interval [CrI], $700 to $141,00) per QALY gained. Notably, smaller increments of increased transplant rates cost more per QALY gained. Investigators believe smaller increases would mean fewer people undergo transplants, along with an increased mean time to transplant, which can result in additional adverse outcomes and costs.

Compared with the status quo, investigators observed a gain of 0.56 QALYs (95% CrI, 0.35 to 0.90 QALYs) and savings of $10,200 (95% CrI, $3400 to $17,900) for older adults.

Even for individuals ≥ 75 years of age, increasing deceased donor transplants by 25% was associated with HRQOL gains and cost $7800 (95% CrI, $1300 to $14,500) per QALY gained.

At a WTP threshold of $100,000 per QALY gained, choosing the status quo as opposed to the 25% increase transplantation rate was predicted to result in an expected loss of $51,400 per person, for a total of $886 million, from the health care sector perspective, and $58,300 per person, for a total of $1 billion, from the modified health care sector perspective.

While the study did not consider the downstream effects of new policies on younger candidates, investigators noted they would expect to see younger candidates benefit from shorter waiting times for all candidates.

Kaufmann MB, Tan JC, Owens DK, Chertow GM, Goldhaber-Fiebert JD. Cost-Effectiveness of Acceptable-Quality Deceased Donor Kidneys for Transplant in Older Candidates. 

https://doi.org/10.1001/jamanetworkopen.2025.55428

Friedewald JJ, Schantz K, Mehrotra S. Kidney organ allocation: reducing discards. 

https://doi.org/10.1097/mot.0000000000001049

Videos

An economic model suggest using lower quality, but acceptable kidneys for older adults may be cost efficective and clinically valuable.

Matthew Kaufmann, PhD

Articles